Ball-and-Socket Limb Support for Surgical Tables
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Solution Overview
Problem
Existing leg stirrups for surgical tables lack a full range of motion adjustment, particularly in the supination/pronation direction, and are cumbersome to manipulate, limiting the ability to position a patient's limb effectively during procedures like gynecologic, urologic, and laparoscopic surgeries.
Innovation Solution
A stirrup-type leg holder with a ball-and-socket mechanism allowing independent adjustment in lithotomy, abduction/adduction, and supination/pronation dimensions, featuring a release mechanism operated by cable, enabling easy repositioning of the stirrup boot relative to the surgical table from the distal end, with a gas cylinder for assistance in movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a traditional adjustable attachment mechanism is used at the proximal end of the leg stirrup, then the stirrup can be attached to the surgical table, but the adjustment is inconvenient for the physician since the adjustment mechanism is located close to the procedure site while the physician is at the distal end
Solution Approach 1:
The patent inverts the traditional arrangement by moving the adjustment mechanism from the proximal end (near the patient's hip) to the distal end (where the physician can easily access it). The stirrup is adjusted by manipulating the attachment mechanism at the distal end, which controls the position of the entire stirrup assembly through the support member.
2Ease of operation
If recent versions of leg stirrups allow adjustment at the distal end, then the physician can easily manipulate the position, but the stirrups fail to provide a full range of motion including supination/pronation direction
Solution Approach 1:
The patent employs a ball-and-socket joint mechanism where a spherical head on the support member fits into a socket at the proximal end. This spherical geometry naturally provides rotation in multiple directions including lithotomy (up/down), abduction/adduction (side-to-side), and supination/pronation (rotational), giving the full range of motion needed while maintaining easy distal adjustment.
3Strength
If the attachment mechanism is located at the proximal end for structural support, then the stirrup can bear the patient's weight, but the physician cannot easily adjust it from the distal end
Solution Approach 1:
The patent divides the stirrup into distinct functional segments: the proximal attachment mechanism for structural support and weight bearing, the intermediate support member for transmission of forces, and the distal adjustment mechanism for easy physician manipulation. This segmentation allows each part to optimize its function without compromising the others.
4Adaptability or versatility
If the leg stirrup allows adjustment in lithotomy and abduction/adduction directions, then it provides good positioning capability, but it does not allow adjustment in the supination/pronation direction
Solution Approach 1:
The ball-and-socket joint with its spherical geometry inherently provides rotation about multiple axes. The spherical head can rotate freely within the socket, enabling adjustment in lithotomy (vertical), abduction/adduction (lateral), and supination/pronation (rotational) directions without requiring complex separate mechanisms for each degree of freedom.
Data Source
AI summary
A limb holder comprising:a mounting bracket for attachment to a surgical table;a mounting element comprising a spheroidal surface for attachment to said mounting bracket;a clamping assembly for providing a clamping engagement about said spheroidal surface of said mounting element, said clamping assembly comprising an upper jaw and a lower jaw, wherein said upper jaw and said lower jaw are biased towards one another so as to provide said clamping engagement about said sphereoidal surface of said mounting element;a limb support element mounted to said clamping assembly via a support rod; anda release mechanism mounted to said support rod and connected to said clamping assembly for selectively releasing said clamping engagement of said clamping assembly about said sphereoidal surface of said mounting element, whereby to allow said limb support element to be repositioned relative to said mounting element and hence repositioned relative to the surgical table.